Prota 2: Vegetables/Légumes
Nicolson, Suresh & Manilal, Interpret. Van Rheede’s Hort. malab.: 88 (1988).
2n = 30
Convolvulus malabaricus L. (1753), Hewittia sublobata (L.f.) Kuntze (1891), Hewittia scandens (J.König ex Milne) Mabb. (1980).
Origin and geographic distribution
Hewittia malabarica is widespread throughout tropical Africa, Asia and Polynesia; it has been introduced and naturalized in tropical America (e.g. Jamaica).
The leaves of Hewittia malabarica are collected from the wild and used as a cooked vegetable. In Uganda they are particularly popular among the Langi people in a dish known as ‘onyebe’. The fibre from the inner bark is used for ropes. In Madagascar Hewittia malabarica is grown as a cover plant in plantations of ylang-ylang (Cananga odorata (Lam.) Hook.f. & Thomson) and is grazed by cattle.
Climbing or prostrate perennial herb with slender stem up to 3 m long, occasionally rooting at the nodes, pubescent. Leaves alternate, simple; stipules absent; petiole up to 9 cm long; blade oblong to ovate, 2–14 cm × 1–10 cm, base cuneate, truncate or hastate, apex obtuse to acuminate, margin dentate or entire, pilose to velvety hairy. Inflorescence an axillary, 1–3 -flowered cyme, bracteate; peduncle up to 10 cm long. Flowers bisexual, regular, 5-merous; pedicel up to 3 cm long; sepals lanceolate to ovate, up to 17 mm long, the outer 3 much larger than the inner 2; corolla campanulate to funnel-shaped, 2–3.5 cm long, slightly lobed, pale yellow or white with a purple centre, pilose outside in 5 bands; stamens inserted in corolla tube, included; ovary superior, 1-celled, hairy, style filiform, stigmas 2, ovate-oblong. Fruit a globose to quadrangular capsule c. 1 cm in diameter, pilose, enclosed by the enlarged sepals, usually 4 -valved, 2–4-seeded. Seeds subglobose, 3–6 mm in diameter, black.
Hewittia is close to Convolvulus, which has linear stigmas. Hewittia comprises only a single species, of which the correct name is still disputed because of differences in interpretation of older literature.
Hewittia malabarica occurs in rainforest, mixed open forest, coastal littoral forest and scrub, along dry watercourses, in grassland and as a weed of cultivated land and along roadsides, from sea-level up to 1800 m altitude. In Uganda it occurs in areas with an annual rainfall of 1100–2100 mm.
Genetic resources and breeding
Hewittia malabarica is very widespread and not liable to genetic erosion.
Hewittia malabarica will remain a locally popular minor vegetable, which is often available when other vegetables are scarce. Its nutritional composition and ornamental possibilities need further investigation.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, United Kingdom. 960 pp.
• Gonçalves, M.L., 1987. Convolvulaceae. In: Launert, E. (Editor). Flora Zambesiaca. Volume 8, part 1. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 9–129.
• Katende, A.B., Ssegawa, P. & Birnie, A., 1999. Wild food plants and mushrooms of Uganda. Technical Handbook No 19. Regional Land Management Unit/SIDA, Nairobi, Kenya. 490 pp.
• Meeuse, A.D.J. & Welman, W.G., 1996. Notes on African plants. Convolvulaceae. Bothalia 26(1): 46–50.
• Deroin, T., 2001. Convolvulaceae. Flore de Madagascar et des Comores, familles 133 bis et 171. Muséum National d’Histoire Naturelle, Paris, France. pp. 11–287.
• Gonçalves, M.L., 1992. Convolvulaceae. Flora de Moçambique. No 113. Instituto de Investigação Científica Tropical, Lisbon, Portugal. 134 pp.
• Verdcourt, B., 1963. Convolvulaceae. In: Hubbard, C.E. & Milne-Redhead, E. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 161 pp.
Correct citation of this article:
Jansen, P.C.M., 2004. Hewittia malabarica (L.) Suresh In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.